电网故障下直驱永磁风力发电机组机侧变流器改进控制策略

Improved machine-side converter control strategy of direct-drive permanent magnet synchronous generator for wind power system during grid failures

文章对电网电压跌落时的直驱永磁同步风力发电机组的低电压穿越过程进行深入研究,在电网电压跌落时,通过分析发电机机侧变流器最大风能跟踪控制策略,提出一种补偿q轴电流参考值抑制直流母线电压的新方法,并加入弱磁控制,使发电机输出功率迅速有效降低,进而维持机侧与网侧变流器的功率平衡及母线电压稳定。电网持续故障且超出规定时间时,为风电机组增加了卸荷电路,保证机组安全退出运行。分析结果验证了所提方案的正确性和有效性。

In order to enhance operational ability of direct-driven permanent magnet synchronous generator （DPMSG） during grid failures,the low voltage ride through of DPMSG was deeply re- searched. The control strategy of maximum wind-power tracking of machine-side converter was analyzed. A new method of compensating current reference of q-axis was proposed to restrain DC bus voltage under grid voltage drops meanwhile the weakening field control was used, which reduced gen- erator output power and balanced the power between machine-side converter and grid-side converter. An unloading circuit was added to ensure that the DPMSG ceases operation safely at the case of con- tinuous grid failure and beyond the prescribed time. Simulation results demonstrate the correctness and practicability of the proposed method.